Electrically operated lift



per/c5 ro Paix/w A. A. CHUBB ELEGTRICALLY OPERATED LIFT l/ff/Y Filed April 19, 1935 46 /1 xmulmull MJA u?" Marax ATT Dec. 29, 1936.

Patented Dec. 29, 1936 UNITED STATES PATENT OFFICE ELECTRICALLY OPERATED LIFT ited, London, England Application April 19, 1935, Serial No. 17,247 In Great Britain June 4, 1934 8 Claims.

This invention relates to electricaly operated lifts, and more especially to such lifts in which the lift driving motor is operated from a motorgenerator set. It has for its object the provision of means whereby the running of the apparatus as a whole is performed under the most economical conditions.

As is well-known, lifts, in common with other forms of public transportation, have busy and slack periods, and in order to provide a certain economy in current, it has hitherto been the practice to provide a time delay device which operates after a predetermined period following the last use of the lift, operation of the said device causing the motor-generator to shut down. This arrangement, though adequate in some respects, is really most suitable for use only during very slack periods. This is because it is found that during busy periods the cost of starting the motorgenerator each time the delay has operated to shut it down approximates to, or is greater than, the cost of the relatively light current taken by the motor-generator when left running on no load.

According, therefore, to the invention, a device adapted to shut down a motor-generator employed in connection with an electrically operated lift after the said lift has been out of use for a predetermined period, is rendered inoperative or ineffective during a particular period or periods by means of a time measuring or time controlled device.

In one embodiment of the invention, a switch or relay in the said time delay circuit is controlled by a clock such that the delay device is inoperative to shut down the motor-generator during certain periods of the day, the said periods being set up on or determined by the clock. The delay device which causes shut-down of the motorgenerator may be a neon blinder circuit-combined with suitable counting apparatus such as a step-by-step switch, or any equivalent device.

In an alternative form of the invention, an electrically driven clock emits an impulse every 30 minutes. These impulses drive a uniselector, the bank of which is divided into, or wired as, 24 or 48 parts, each part representing one hour or one-half hour. This selector, by means of keys, rotatable hand-operated switches or jumpers allows a certain number of periods during the day to be selected in which the motor-generator shut-down is put out of action.

Reference should now be made to the accompanying drawing, in which Figure 1 is a delay circuit, Figure 2 is a pOftQrl. Qf a typical lift system, and Figures 3 and 4 are alternative means of preventing the operation of the apparatus in Figure 1 at various predetermined periods. The circuit as a whole is applicable to any system of lift control employing inductor type relays or like devices in the lift shaft for levelling, floor counting and such purposes, and in which the lift driving motor is supplied with current from a Ward-Leonard motor-generator set. The invention is, of course, not limited to this particular type of lift controlling system, but can be applied with suitable modifications to any similar form of electrical lift controlling system which requires one or more delay periods.

In Figures 1 and 2, a motor DM, which is arranged to be energized by potential through contacts gl over line 8 to earth el, drives an electric generator WL which is connected up, in accordance with the well-known Ward-Leonard or variable voltage principle, through earth e2 and line 8M with a motor LM adapted to drive the winding drum of the lift. The circuit 9M from the lift motor LM extends through or is controlled by suitable relays RLM vand lead 9 through contacts 'm'l The lift car L and counter-weight are attached in the usual manner to the opposite ends of the hoisting cable which passes over the winding drum.

The eld winding l1 of the Ward-Leonard generator WL is preferably coupled up with circuits of any Well known character arranged to control the direction and speed of rotation of the lift driving motor LM. These form no part of the present invention and are not shown but such circuits are described, for example in a co-pending application Serial Number 738,963, led August 8, 1934.

In order to facilitate readily stopping at the various floors a slow down inductor relay S, is mounted on, although shown separate from the lift car L, and arranged to be operated by inductor plates I9 provided in the lift shaft; the plates I9 being so arranged that the relay S is operated just before a floor level is reached by the lift car L.

The inductor relay S, when operated by one of the inductor plates I9, closes contacts sl, which through lead I2 operates a slow down relay SD just before a floor level is reached. When relay SD operates, contacts Sdl, operating through lead I0 and a plurality of gate-operated switches JA to JF, one for each floor, and through lead Il and contacts tpZ provides a holding circuit for the relay SD; and relay SD operates contacts sd2 to prepare an operating circuit for a Hoor operated relay NR, which is operated when the floor level is reached, to cut out the lift motor, the arrangement being such that opening a gate switch JA to JF will prevent operation of the lift. The relay SD also operates contacts 8d3 which prepare a short circuiting path across the resistance RB as later described.

Another inductor relay T which is mounted in the lift car L, but for clarity is shown separate therefrom, is provided for operating floor operated relay NR. Inductor plates I8 for operating inductor relay T are provided in the lift shaft and so arranged that when the lift car L is standing at any floor level the relay T remains operated. The floor operated relay NR, when operated by the inductor relay T through leads 3 and 3a and contacts sdZ, opens contacts nrl, previously referred to, and this will stop the lift motor LM, which will remain inactive while the lift is held at a floor. The floor operated relay NR also operates contacts m2 which, with contacts sd3, as explained later, complete a short circuiting path across the resistance RB.

Push button or other lift control apparatus of the usual or any well known type, not shown, may conveniently be employed and may be of the type disclosed in said co-pending application Ser. No. 738,963, is arranged to operate a delay circuit relay C over the lead 2. The delay circuit relay C is preferably arranged to be maintained operated by means of the push button control apparatus while the system is engaged in answering a call but is released when the circuit in the lead 2 is opened by the push button control apparatus when the lift stops at any floor, but the means for operating this circuit is not shown, for the push button control apparatus forms no part of the present invention and such an arrangement will be perfectly obvious to those skilled in the art.

The delay circuit relay C, when operated, opens contacts cI which in their closed position prepare an operating circuit for parking devices and a parking relay D, i. e. the relay and parking devices are arranged to be operated when the lift car has to be returned to a particular floor at which it is required normally to be parked, and, as explained later, the parking relay D operates to open contacts dl in lead 2 of the circuit to the delay circuit relay C.

The delay circuit relay C also operates contacts c2 which prepare a stepping circuit for the stepping magnet TS of a step-by-step switch of the type in use in automatic telephone systems and which here is provided with wiper contact banks TSI, TS2, TS3 and TS4, the functions of which are described later.

The delay circuit relay C, upon operation, opens contacts c3 which when closed are adapted to complete a circuit from the direct current supply D. C. to a delay circuit, as hereinafter described.

An important function of the delay circuit relay C is to close contacts c4 which complete a circuit for operating a motor starting relay G.

The motor starting relay G operates the contacts gl which, as previously pointed out, are included in the circuit with lead 8 of the motor DM which drives the generator WL. And comtacts g2 operated by relay G prepare the connecting circuit between the supply D. C. and the delay circuit.

The delay circuit includes a neon tube B connected by lead 20 from a D. C. source and leads 2|, 22 in series with a delay-period relay TP, these two elements being connected in parallel with a condenser A by means of leads 23 and 24. One side of the tube B and one side of condenser A are connected through lead 25 with resistance RA and RB which are connected in series by lead 26, and connected through contacts c3, lead 2`I, contacts g2, when closed, and lead 28 with the direct current supply D. C. which may be a public supply, or may be obtained by an A. C./D. C. converter of any known form op erated from alternating current mains. The supply is preferably in the region of ZOO-250 volts.

A circuit for short-circuiting the resistance RB is provided by lead 29 through contacts m2, when closed, lead 30, contacts sd3, closed, and lead 3|, which is connected at the junction of lead 26 with RA.

The delay-period relay TP, included in the delay circuit, is arranged to be operated, as hereinafter described, after the elapse of predetermined delay-periods depending on the characteristics of the delay circuit; i. e. whether one or both resistances RA, RB are in circuit.

The delay-period relay TP operates contacts tpl which, through connecting leads 32, 33 extending between leads 22 and 25, are arranged to cause condenser A, in the delay circuit, to

discharge substantially completely through the coil of the delay-period relay TP, because in this manner the tube B is short-circuited.

And contacts tp2, operated by relay TP, are arranged to perform two functions, First, tpZ

normally on the lower contact, as previously ex- :V

planed, completes the holding circuit of the slow-down relay SD and, when this contact is opened by operation of relay TP, the relay SD will be released, that is after it has been operated by the inductor relay S, as above described. Second, the upper contacts of tp2 are arranged to close a stepping circuit through lead 34, Wiper and connected contacts of stepping switch TSI, lead 35, contacts c2, lower position, and lead 36, of the switch magnet TS.

The stepping magnet TS, which under conditions hereinafter explained, rnay be self stepped by means of its contacts ts when the delay circuit relay C operates contacts c2 to close lead 36 on the upper contact, which, being connected through lead 31, contacts ts, lead 38, interconnected wiper contacts and Wiper TS2, supplies potential for the self-stepping of the switch.

The delay circuit relay C by closing contacts C4, previously referred to, through lead 39 provides operating potential for the motor starting relay G. The starting relay G is arranged to be retained operated for a time by interconnected contacts of wiper switch TS4, supplying potential through leads 40 and 39 as described later.

One other circuit is controlled by the delay circuit relay C. When the delay circuit relay C is deenergized contacts cI, closing on the lower contact, permits the impulse circuit from tp2 through leads 34 and 35 to pass from the latter through lead 4|, contacts cI lead 42 Wiper of TS3 and the fifth contact thereof, after the switch has been stepped that far, through lead 4 to operate the parking relay D and the parking devices by way of lead 4a.

As an example under operating conditions, with the D. C. supply connected to the circuit as shown, (contacts g2 closed) the condenser A commences to charge at a rate determined by the values of the reslstances RA and RB. After a time, the potential across the condenser A reaches a value equal to that of the striking potential of the tube B, which then becomes conductive, allowing a current to flow from the condenser A through the coil of the delay period relay TP and the relay operates. Assuming now that contacts tpl are not, for the moment, present, when the potential across the condenser A (which potential during discharge, falls rapidly), reaches the extinguishing value of the tube B, this value being usually between 30 and 40 volts lower than the striking value, the tube becomes once more non-conductive and the relay releases. This operation is repeated, the condenser charging once more to the striking potential of the tube and discharging through it, at a rate proportional to the size of the condenser, the value of the resistance in series, and the supply voltage, so that a time delay of a predetermined value is obtained between the application of the supply voltage to the resistance-condenser combination, and the operation of delay period relay TP.

As may be seen from the foregoing example, however, the initial charging period of condenser A is longer than that of subsequent periods since in the first case the voltage rise is from zero to the striking potential of tube B, whereas in subsequent cases the voltage rises only from the extinguishing potential to the striking potential of the tube. In addition, the current derived from the condenser during the fall of potential experienced Whilst the condenser is discharging (from striking to extinguishing value) through the tube is apt to be small, and requires a delicate relay to respond adequately thereto. Use is, therefore, made of contacts tpl Which shortcircuit the tube B as soon as delay period relay TP operates, allowing condenser A to discharge substantially completely through the relay coil at each operation of the relay, thus ensuring not only that the condenser charges from zero each time, but also that the relay receives an adequate operating current.

The two resistances RA and RB, the values of which are such that delay period relay TP does not remain held operated in series with them to the supply D. C. are employed in order to obtain two rates of delay. As will later be seen, diierent delay periods may be required to control different lift operations, and as the delay period obtained from the tube B increases as the time for charging condenser A increases, and this increases with increase of resistance in the circuit, a short delay period is therefore, obtained by supplying current through resistance RA only, whilst resistance RB is included in series when a longer delay is required.

Referring to the remainder of the circuit, during normal operation of the lift, delay periods of certain lengths are required, notably a relatively short period, after the lift has reached a floor, during which the gate may be opened. This period is necessary in order to ensure that the lift does not restart immediately it has stopped at a floor, to answer a call made from another oor. This period is usually of the order of 5 seconds.

A further delay is that employed when the lift has been out of use for some time, say one minute. It is usually required to restore the lift to a parking floor at the end of this period, this floor being the one from which calls are most likely to originate, e. g. the ground floor.

After a still :further period, it may be required to shut down the Ward-Leonard motor-generator set DM-WL if no calls are made for the lift during that period, though should calls be made for the lift at any time during these last two delay periods, all delay apparatus must be restored to normal in readiness for repeating a cycle when the lift once more goes out of use.

While the lift is actually engaged in answering a call, the delay circuit relay C is maintained operated, as above described, from push button control over lead 2. Contacts gI and g2 are closed, as the motor starting relay G is normally held operated over lead 4l] from bank TS4 of the stepping switch TS.

At a point in the lift shaft prior to the floor at which the lift is required to stop the inductor relay S is operated by inductor plate I9 in the shaft and its contact sl operates the slow-down relay SD over lead I2, the contacts sdI immediately completing a holding circuit through lead l0, the gate switches JA-JF lead I I to tp2. The lift is slowed down and when the floor is reached inductor relay T is operated by inductor plate I8 associated with that floor; contacts tI thereupon close and cause actuation of floor operated relay NR through lead 3, 3a and contacts sd2, which by opening contact mI in lead 9 stops the lift motor LM.

So long as floor operated relay NR is operated the lift motor LM cannot be energized, but operation of relay NR is dependent upon the operation of the slow-down relay SD, since its circuit is completed through contacts 8d2, and when relay SD is deenergized by the opening of one of the gate-operated switches JA, JA JF, i. e.

when the lift gates or the floor gates are opened, thus breaking the holding circuit from contacts tp2 the opening of contacts sd2 releases the relay NR to prepare the energizing circuit of the lift motor LM.

If, when the lift has arrived at the oor to which it has been called or taken, the gates are not opened, i. e. holding circuit of relay SD not broken, the lift does not move away from that floor immediately since the floor operated relay NR remains energized. However, after a predetermined delay-period the delay-period relay TP operates and its contacts tp2 opens the holding circuit I I, JA-JF, I0, sd I, SD and releases the slow-down relay SD. which in turn, at its contacts sd2 releases the floor operated relay NR. This predetermined delay-period, of say 5 seconds, is determined by resistance RA only, as the contacts m2 and S113. in the circuit 29, 30, 3 I, are

both closed (NR and SD operated) the resistance RB is short-circuited.

When the delay-period relay TP operates mo-A mentarily at the end of the rst delay period. as just indicated. contacts tp2 by way of the upper contact energize the stepping magnet of the switch TS through lead 34 via bank lTSI thereof, lead 35, contacts c2 and lead 36. When delayperiod relay TP subsequently releases, contacts tp2 open and deenergize the stepping magnet and the switch TS makes one step advancing the Wipers of all banks to contacts No. 2 in their banks. After this first operation of delay-period relay TP, which operation. by breaking the holding circuit at tp2 of slow-down relay SD, opens contacts sd3 and removes the short-circuit from resistance RB. and. provided that no further calls are made for the lift in the meantime, i. if delay-circuit relay C remains deenergized, the delay circuit is supplied through both resistances RA and RB so that when the delay-period relay TP is operated a second time, it will be after a longer delay-period, e. g. 15 seconds instead of 5 seconds.

Upon successive operation of the delay-period relay TP, the switch TS is stepped via contact no2 lead 34 and the bank TSI as explained. It will be observed that when the wiper of bank TS3 reaches its fth contact it stands on a contact connected with the lead 4 and, at the commencement of the fifth stepping impulse derived from the contact tp2, potential is momentarily applied to this lead 4 via lead 34, connected contacts on bank TSI, leads 35, 4I, contacts cI lead 42 and bank TS3. This potential is applied via lead 4 to parking relay D and through 4a to a parking device of well known character, which, when operated, has the effect of calling the lift to the parking floor. However, an essential difference between a parking call and one made by an` intending passenger is that the switch TS is not re-set to a zero position owing to the operation, Ain the case of the former type of call, of the parking relay D, the contact dI of which prevents re-energization of delay-circuit relay C and therefore, self-operating circuit through contact c2, as hereinafter described, cannot function.

The lift now travels to the parking oor and then stops, the delay-circuit relay C remaining deenergized. The delay-period relay TP will continue to impulse the stepping magnet of the switch TS, via contacts tp2 and bank TSI, until the wiper of the bank TS4 leaves the end of the row of connected contacts on that bank; the motor starting relay G is then deenergized through lead 48 and releases so that the contacts gl open the circuit of the motor DM of the motorgenerator set DM-WL, thus causing shut-down of all the energized plant. Contacts g2, at the saine time open and disconnect the supply DC from the delay circuit which operates delayperiod relay TP, so that switch TS is no longer impulstd through contacts tpZ.

Everything remains in this condition until a further call is made for the lift by an intending passenger. When a passenger call is made the delay-circuit relay C then reoperates, and its contacts c2, in the upper position by way of lead 31 connect the stepping magnet of the switch TS through its interrupter contacts ts and lead 38 to f bank TS2, all the contacts except the first of which bank are connected together. The switch TS now steps by self-interruption in known manner until the wiper of bank TS2 rests on its first contact, whereupon stepping ceases. In the meantime contacts c4 through lead 39 reoperate motor starting relay G and contacts gl thereof restart the motor-generator set. All the apparatus is then ready once again to repeat the whole or in part the cycle of operations above described.

From the foregoing it will be seen that after the lift has remained out of operation for a period of say three minutes it will have reached a parking position and the motor-generator set from which its operating current is derived will have been shut down. In order to restart the lift, however, a considerable amount of energy is required to accelerate the armatures of the Ward-Leonard set. and in addition a certain quantity of energy is necessarily wasted in starting resistances. It is found that at certain periods of the day this quantity of energy is equal to or in excess of the relatively small amount which is employed in maintaining the motorgenerator set running under no load. It is therefore economical to prevent the shut-down of the motor-generator set under such conditions, though such intervention must not affect the delay periods provided in connection with the gate opening and parking operations.

This may be accomplished, as shown in Figs. 3 and 4, which show alternative means of suspending the shut-down function of the circuit without affecting the other delays. In Fig. 3, there is shown a device consisting of an arm H which is iotated once every 24 hours by any known form of clockwork mechanism. This arm engages with the inner ends of a number of screws J inserted in holes in an annular conducting drum K, 24 or 48 holes, as may be desired being provided in the circumference of this drum. The holes correspond to the positions occupied by the Wiper H during any hourly or half-hourly period of the day, and screws or other removable contacts are inserted in holes corresponding to a period when the shut-down function is to be suspended. The contact ring or drum K is connected by means of lead I4 (through lead 39, Fig. l) to motor starting relay G, so that when the clock mechanism causes the arm H to rest in contact with any of the screws in the drum, an earth potential is applied from the arm H via the screw J, the ring K and lead I4 to hold motor starting relay G operated, the contact gI of which maintains the Ward-Leonard set running in spite of any operations of delay-circuit relay C or the switch TS, i. e. wiper TS4 may move off the row of connected contacts in its bank, and relay C may release, without releasing motor starting relay G.

However, relay G being operated, contacts g2 will be closed so that delay period relay TP will continue to be operated and switch magnet TS will continue its step-by-step movement of the wiper switches until the wiper TSI arrives on the last contact of its bank, which, as will be seen, is not connected with the others so that the circuit from tpZ through lead 35, contacts c2 and lead 3B to the magnet TS is broken.

An alternative method of performing the same function is shown in Fig. 4. In this figure a contact P is operated momentarily at the end of each period of time of a certain length, e. g., once every 30 minutes, by means of a clock of known form having contacts arranged in any well known manner. This contact P, through lead 45 is adapted to energize and release switch magnet W, each energization causing wipers of wiper switches WI, W2 and W3 to advance one step in their banks in the direction of the arrows. I

Each bank of wiper switches WI and W2 is shown as containing 24 contacts, each contact being wired by leads 45 to a corresponding terminal on a terminal strip M. These terminals may be connected together, as indicated at ml, m2, in a manner corresponding to the time of day during which it is required to suspend the operation of the shut-down feature. The suspending groups mi, m2 are connected to a common lead 41 which by lead I4 is connected to the motor starting relay G through lead 39. Each wiper WI and W 2 as shown is single ended, and while one wiper rotates through 180 over its associated set of 24 contacts, the other wiper is out of contact with its own bank, thus previding in effect a single wiper switch having 360i of rotation and 48 contacts. By altering the connections ml, m2, on the terminal strip M, it is possible to hold motor starting relay'G operated for any required Vperiod during'the day, the holding circuit from relay G 75 passes through leads 39, i4, 41 and the connected contacts in the terminal strip M via the banks and wipers WI and W2 to earth potential on the key E. The contacts ce of key E are normally closed, but if it is required for any reason to suspend the operation of the control device as shown in Fig. 4, the key E is operated and contacts ee opened, thus preventing motor starting relay G from being held when either of the wipers Wl or W2 stands on a contact connected to relay G through the circuit described via lead I4. If required, other suitable switches or connections may be employed instead of the terminal strip M, but they might be less reliable and more expensive.

As an obvious alternative to the clock controlled contact P, the delay or timing circuit substantially as shown in Figure 1 could be employed. In that case the circuit would be provided with such resistance and so arranged that the neon tube becomes conductive at the end of an additional period, say half a minute; the delay period relay 'I'P in series with the tube, would then be energized at the end of each half minute period, and a contact (i112 or another) associated with this relay would impulse the stepping switch which then would be provided with another switch bank adapted to supply an impulse to the switch magnet W (Fig. 4) once every half hour. Although the delay-period device would not provide impulses of such constancy as that derived from a clock, owing to variations usually present in any form of public current supply such as D. C., such impulses would be of suilicient accuracy to enable the lift to be controlled throughout a period of one day, the switch W being then reset to a particular position. This resetting operation of course could be performed manually, but preferably it is done by means of a special bank W3 on the switch W in Fig. 4 cooperating with a clock-controlled contact operating once every 24 hours only. In the resetting arrangement shown in Figure 4, it will be seen that all the contacts except one of the special bank W3 are connected together and to lead l5, which, as previously indicated, may be connected to the clock-controlled contact which connects earth potential to lead l5, the latter potential being supplied through wiper and bank W3, lead 48 to the stepping magnet of the switch W via self interrupter contacts I6, to step the switch by self-interruption in known manner until the wiper arrives at the single isolated contact, from which operations are recommenced.

I claim:-

1. An electrically operated lift controlling system having means adapted to shut down a motorgenerator when the lift has been out of use for a predetermined period, characterized in that the said means is rendered inoperative or ineffective during a particular period or periods by means of a time measuring or time controlled device.

2. An electrically operated lift controlling system according to claim l, characterized in that shut-down of the motor-generator set is prevented by means of a clock driven arm co-operating with a bank of removable contacts connected to a relay, release of which normally stops the motor-generator, the contacts being positioned so as to prevent release of the relay during a predetermined period or periods.

3. A lift controlling system according to claim l, in which shut-down of the motor-generator set is prevented by means including a step-by-step switch, a terminal or connecting strip connected thereto and means for impulsing the said switch at a steady rate.

4. An electrically operated lift controlling system according to claim 1, in which shut-down of the motor-generator set is prevented by means including a step-by-step switch, a terminal or connecting strip connected thereto and means for impulsing the said switch at a steady rate, said impulsing means comprising clock controlled contacts.

5. An electric lift controlling system according to claim l, in which shut-down of the motorgenerator set is prevented by means including a step-by-step switch, a terminal or connecting strip connected thereto and means for impulsing the said switch at a steady rate, said impulsing means comprising a neon delay or blinker circuit.

6. In an electrically operated lift controlling system the combination with a motor for operating the lift, of a relay for operating the lift motor, delay-period means adapted to maintain said relay actuated and the motor operating While said delay-period means is in operation for effecting normal delay periods, and clock controlled means for maintaining said relay operated for preselected definite periods during the day, independently of said delay-period means.

7. In an electrically operated lift controlling system the combination with a motor for operating the lift, of a. relay for operating the lift motor, delay-period means adapted to maintain said relay actuated and the motor operating while said delay-period means is in operation for effecting normal delay periods, clock controlled means comprising a step-by-step wiper switch, having at least one bank of contacts, arranged to be stepped at predetermined intervals by the clock and terminal means for connecting certain of said contacts together for maintaining said relay operated for preselected definite periods during the day, independently of said delay-period means.

8. In an electrically operated lift controlling system the combination with a motor for operating the lift, of a relay for operating the lift motor, delay-period means adapted to maintain said relay actuated and the motor operating while said delay-period means is in operation for effecting normal delay periods, means comprising a step-by-step Wiper switch, having at least one bank oi contacts, arranged to be stepped at predetermined intervals, terminal means for connecting a plurality of adjacent contacts together for maintaining said relay operated for preselected deiinite periods and blinder controlled impulse means for stepping said switch at predetermined intervals.

,ALEXANDER ALBER'I` CHUBB. 

